Nested core gas turbine engine

ABSTRACT

An aircraft, with the ability to cruise at supersonic speeds, designed to increase cruise lift/drag ratio, reduce sonic boom and have greater downward visibility by having an ‘inverted’ nose profile that has greater inclination of the lower surfaces to the flight direction than the upper surfaces.

RELATED APPLICATION(S)

This application is a continuation from co-pending application Ser. No. 12/537,045, filed Aug. 6, 2009, which is a continuation from Ser. No. 11/682,077, filed Mar. 5, 2007, which is a continuation from application Ser. No. 11/201,441, filed Aug. 10, 2005 which is a continuation from application Ser. No. 10/635,956 filed Aug. 7, 2003, now issued U.S. Pat. No. 6,988,357, which is a continuation from application Ser. No. 09/947,002, filed Sep. 5, 2001, now issued U.S. Pat. No. 6,647,707, which claims the benefit of U.S. Provisional Application No. 60/230,891, filed Sep. 5, 2000, and of which are incorporated by reference herein in their entireties.

FIELD

The disclosed embodiments relate to supersonic aircraft.

Previous Developments

Conventional supersonic aircraft, such as the Concorde, have a sharp, needle-type, quasi-conical nose, that is designed to minimize the strength of the shock waves formed when the aircraft is traveling at supersonic speeds. This nose is generally somewhat angled down, looking forward from the cockpit, to enable downward visibility for the pilots. Examined another way, the tip of the nose, viewed from the side of the profile, is located below the centerline of the fuselage behind the nose.

This conventional design of the nose for conventional supersonic aircraft is not advantageous from the viewpoint of aerodynamic performance. The quasi-conical nose acts as a supersonic ramp that compresses oncoming air. Because the ramp is not axi-symmetric, the ramp has a greater angle to the flight direction on a part of the surface, such as the upper surface in a conventional aircraft, and has a smaller angle to the flight direction on another part of the surface, such as the lower surface in a conventional aircraft. The intensity of the supersonic shock waves thus formed along the angled surfaces of the quasi-conical nose are not symmetric with respect to the flight direction. Parts of the curved surface of the nose that have a greater angle to the flight direction have a greater intensity of shock, and other parts of the curved surface of the nose have a lesser intensity of shock. It is well known that a greater intensity of shock creates a greater increase in static pressure of the flow, that is the pressure normal to the local surface.

The shockwaves on the nose surfaces also create drag for the aircraft, due to a combination of pressure drag and increased skin friction drag.

In conventional aircraft, with the nose angled down from the fuselage, the upper part of the nose has the greater intensity of shock and the greater static pressure, compared to the lower part of the nose. As a result, the nose experiences a net downward force.

BRIEF DESCRIPTION OF THE DRAWINGS

The foregoing aspects and other features of the exemplary embodiments are explained in the following description, taken in connection with the accompanying drawings, wherein:

FIGS. 1-1A respectively are a schematic cross-sectional view and a schematic perspective cut-away view of a gas turbine engine incorporating features in accordance with a first embodiment;

FIG. 1B is a perspective view of the gas turbine engine in FIG. 1;

FIG. 1C is a perspective view of the front section of an outer casing of the turbine engine in FIG. 1;

FIG. 1D is a perspective view of a front rotor of the turbine engine in FIG. 1;

FIG. 1E is a perspective view of a stator section of the turbine engine in FIG. 1;

FIG. 1F is a perspective view of a rear rotor of the turbine engine in FIG. 1;

FIG. 1G is a perspective cut-away view of a rear end portion of the turbine engine in FIG. 1;

FIGS. 2A-2B are graphs respectively illustrating power/weight ratios versus rated power, and specific fuel consumption (SFC) versus rated power for small engines of the prior art;

FIG. 3 is a cross-sectional view of a gas turbine engine in accordance with a second embodiment;

FIG. 4 is a graph showing variation of ignition delay time at a number of air temperatures with respect to pressure in accordance with the prior art;

FIGS. 5 and 6 are respectively schematic cross-sectional views of a conventional engine with centrifugal compressors and wrap-around burners, and a conventional engine with axial compressors and in-line burners;

FIGS. 7-10 respectively are schematic cross-sectional views of a turbo-jet engine, turbo-fan engine, high-bypass ration turbo-fan engine, and ultra-high bypass ratio turbo-fan engine in accordance with other embodiments;

FIGS. 11-12 respectively are schematic cross-sectional views of the propulsion systems of high speed air vehicles in accordance with still other embodiments;

FIGS. 13 and 14-14A respectively are schematic top plan, elevation, and bottom plan views of an unmanned aerial vehicle (UAV) in accordance with yet another embodiment;

FIGS. 14B-14C respectively are schematic side elevation and rear elevation views of the UAV in FIG. 13 in a first mode of operation (e.g. cruise mode), and FIGS. 15A-15B respectively are schematic side elevation and rear elevation views of the UAV in FIG. 13 in a second mode of operation (e.g. hover mode);

FIGS. 16-17 are graphs respectively illustrating the relationship of thrust to engine diameter and engine frontal area for field engines of the prior art and gas turbine (nested core) engines according to the exemplary embodiments;

FIG. 18-19 are graphs respectively illustrating SFC at rated thrust versus operating pressure ration (OPR), and thrust versus OPR for field engines of the prior art and gas turbine engines of the exemplary embodiments;

FIGS. 20-21 are graphs respectively illustrating SFC at rated thrust versus rated normal thrust, and length/diameter ratio versus engine diameter for field engines of the prior art and gas turbine engines of the exemplary embodiments;

FIGS. 22-23 are graphs respectively illustrating thrust versus engine volume and bulk density (engine weight/cylindrical volume) versus engine diameter for field engines of the prior art and gas turbine engines of the exemplary embodiments;

FIGS. 24-25 are graphs respectively illustrating thrust versus weight, and thrust/weight versus thrust for field engines of the prior art and gas turbine engines of the exemplary embodiments;

FIG. 26 is a schematic cross-sectional view of a gas turbine engine in accordance with another embodiment, particularly useful for a larger (scaled-up) engine;

FIG. 27 is a schematic cross-sectional view of a gas turbine engine in accordance with yet another embodiment, also particularly useful for a larger (scaled-up) engine;

FIG. 28 is a schematic cross-sectional view of a gas turbine engine in accordance with still another embodiment, also particularly useful for a larger (scaled-up) engine;

FIGS. 29-29A are a schematic cross-sectional views of a gas turbine engine in accordance with still other embodiments;

FIGS. 30A-30D are respectively schematic front elevation, plan, rear elevation and side elevation views of a high speed air vehicle embodiment according to the exemplary embodiments;

FIGS. 31A-31D are respectively schematic front elevation, plan, rear elevation and side elevation views of the high speed air vehicle in FIG. 30A; and

FIGS. 32A-32D are respectively schematic front elevation, plan, rear elevation and side elevation views of another high speed air vehicle embodiment according to the exemplary embodiments.

DETAILED DESCRIPTION OF THE EXEMPLARY EMBODIMENTS

FIGS. 30A-30D, 31A-31D and 32A-32D show examples of high-speed aircraft embodiments 1000-1000′ that use alternative embodiments of the nested core engines in a lift-fan configuration, deriving benefit from the short axial length of the nested core engines. Alternative aircraft embodiments can be made using the nested core engines in similar aircraft configurations.

The aircraft 1000, 1000′ shown in FIGS. 30-32 has a nose 1010 pointing above the fuselage centerline, such that the tip 1012 of the nose is above the fuselage centerline 1000CL (see FIG. 30D).

The aircraft shown in FIGS. 30-32 has a nose region 1014 configured to have greater inclination a to the flight direction (indicated in by arrow V in FIG. 30D, during supersonic cruising flight, on its lower surfaces 1014L as compared to its upper surfaces 1014U.

The aircraft shown in FIGS. 30-32 has a nose region 1014 configured to have greater intensity of inclined shock waves, during supersonic cruising flight, on its lower surfaces 1014L as compared to its upper surfaces 1014U.

The aircraft shown in FIGS. 30-32 has a nose region 1014 configured to have greater static pressure, during supersonic cruising flight, on its lower surfaces 1014L as compared to its upper surfaces 1014U.

The aircraft shown in FIGS. 30-32 is configured to derive net positive lift (indicated by arrow V in FIG. 30) from the nose region 1014 during supersonic cruise conditions.

The aircraft shown in FIGS. 30-32 has greater cockpit window areas 1014W on the lower surface 1014L of the nose rather than the upper surface 1014U of the nose 1010. 

1. An aircraft for supersonic operation at least some of the time, said aircraft having a nose pointing above the fuselage centerline, such that the tip of the nose is above the fuselage centerline.
 2. An aircraft for supersonic operation at least some of the time, said aircraft having a nose region configured to have greater inclination to the flight direction, during supersonic cruising flight, on its lower surfaces as compared to its upper surfaces.
 3. An aircraft for supersonic operation at least some of the time, said aircraft having a nose region configured to have greater intensity of inclined shock waves, during supersonic cruising flight, on its lower surfaces as compared to its upper surfaces.
 4. An aircraft for supersonic operation at least some of the time, said aircraft having a nose region configured to have greater static pressure, during supersonic cruising flight, on its lower surfaces as compared to its upper surfaces.
 5. An aircraft for supersonic operation at least some of the time, said aircraft deriving net positive lift from the nose region during supersonic cruise conditions.
 6. An aircraft for supersonic operation at least some of the time, said aircraft having greater cockpit window areas on the lower surface of the nose rather than the upper surface of the nose. 